Interposer And Manufacturing Method For The Same

ABSTRACT

In a manufacturing method for an interposer, a seed layer is formed at an opening portion in a through hole on back surface side of a substrate, an electrode layer for electroplated coating is formed based on the seed layer, and an electroplated coating layer is formed to fill the through hole from the electrode layer for electroplated coating layer to a front surface side. As a result, a manufacturing method for an interposer is provided in which the manufacturing process is simple and the void is not generated inside of the through hole.

TECHNICAL FIELD

The present invention relates to an interposer and a manufacturingmethod for the same, and more particularly, relates to an interposer anda manufacturing method for the same in which a pinch-off is notgenerated in a through hole.

BACKGROUND ART

An interposer in which a conducting hole is prepared on a substrate inthe prior art technology, is disclosed, for example, in JapaneseUnexamined Patent Publication 2004-165291.

According to the above described Unexamined Patent Publication, astructure is disclosed wherein a conducting member is formed such that adiameter of the conducting member becomes larger or smaller insuccession or in incremental steps from one side to another side in theceramic substrate which has laminated greensheets of a plurality ofthrough holes arranged in a predetermined pattern and filled with theconducting member, and a plurality of another through holes arranged inthe same pattern having different diameters.

FIG. 9 is a cross sectional view to show a silicon substrate 80explaining a problem in the prior art technology when an interposer ismanufactured by arranging a conducting hole on the silicon substrate 80.Referring to FIG. 9, in the prior art technology, firstly a through hole91 is formed on the silicon substrate 80. At this point, the throughhole 91 becomes a cylindrical shape whose center portion is concave asshown in FIG. 9 rather than straight.

For the through hole 91, seed layers 83, 84 are formed by sputteringaround the through hole 91 from both of a front surface 81 and a backsurface 82. Then, conducting layers 85, 86 are formed by electroplatedcoating and the like utilizing the seed layers 83, 84 as a seed.

The interposer in the prior art technology is constituted as describedabove. According to the Unexamined Japanese Patent Publication2004-165291, because the ceramic substrate is utilized and drilling orsand blasting is employed to open holes on the substrate, there is aproblem that a diameter of the through hole cannot be made small.Moreover, because it is necessary to agglutinate two ceramic substrates,there is a problem that a manufacturing process becomes complicated.

Further, when the through hole is formed on the silicon substrate,because the center portion of the through hole has the concave shape anddiameter of the through hole becomes larger as it goes inside from thefront surface or the back surface, the seed layer cannot be formed wellinside even when the seed layer is intended to be formed inside of thethrough hole. As a result, even when the conducting layer is grown fromthe seed layer by the electroplated coating and the like, because theconducting layer is not grown enough, so called “void” 92 is formedinside of the through hole 91, in which the conducting layer does notexist. This causes a problem that the through hole 91 is not conductiveand the manufacturing precision is poor.

DISCLOSURE OF THE INVENTION

The present invention is made to solve the above described problems andit is an object of the present invention to provide an interposer andmanufacturing method for the same in which the manufacturing process issimple and the void is not generated inside of the through hole.

In accordance with one aspect of the present invention an interposerincludes: a substrate which has one surface and another surface opposedto the one surface; a through hole being formed from the one surface tothe another surface; a seed layer which is formed at an opening portionof the through hole on the one surface side of the substrate; anelectrode layer for electroplated coating which is formed by coveringthe seed layer; and an electroplated coating layer which extends fromthe electrode layer for electroplated coating to the another surfaceside to fill the through hole.

Because the interposer according to the present invention includes theseed layer which is formed at the opening portion of the through hole onthe one surface side of the substrate, the electrode layer forelectroplated coating which is formed by covering the seed layer, andthe electroplated coating layer which extends from the electrode layerfor electroplated coating to the another surface side to fill thethrough hole, the electroplated coating layer can be surely formed fromthe seed layer on the one surface side of the substrate to the anothersurface side.

As a result, an interposer can be provided in which the manufacturingprocess is simple and the void is not generated inside of the throughhole.

The through hole may have a shape whose center portion is concave.Further, the seed layer, the electrode layer for electroplated coatingand the electroplated coating layer may be made out of the samematerial, or may be different materials.

In accordance with another aspect of the present invention, amanufacturing method for interposer includes steps of: preparing asubstrate which has one surface and another surface; forming a throughhole on the substrate; forming a seed layer at an opening portion of thethrough hole on the one surface side; and filling the through hole byforming an electroplated coating layer from the seed layer on the onesurface side to the another surface side.

The manufacturing method for the interposer according to the presentinvention includes steps of forming a seed layer at an opening portionof the through hole on the one surface side and filling the through holeby forming an electroplated coating layer from the seed layer on the onesurface side to the another surface side. Because the conducting layeris surely formed by the electroplating from the one surface side of thethrough hole on the substrate to another surface side, the void is notgenerated inside of the through hole.

As a result, a method for manufacturing the interposer can be providedthat is simple and the void is not generated inside of the through hole.

Preferably, the step of filling the through hole by forming anelectroplated coating layer from the seed layer on the one surface sideto the another surface side includes steps of forming an electrode layerfor electroplated coating to close the through hole at the one surfaceside, and forming the electroplated coating layer utilizing theelectrode layer.

More preferably, the step of forming the through hole includes a step offorming a through hole whose center portion becomes concave.

At this point, the seed layer, the electrode layer for electroplatedcoating and the electroplated coating layer may be made out of the samematerial, or different materials.

In accordance with still another aspect of the present invention, aninterposer includes a through hole which is made from a surface of oneside of the substrate to a surface of another side, the through hole hasa first opening area at the surface of the one side, and has a secondopening area at the surface of the another side, and both of the firstopening area and the second opening area become smaller in succession asthey go from the surfaces to inside, and the interposer also includes aconducting layer which is formed in the through hole.

Because the interposer has the through hole whose opening area becomessmaller in succession as they go from the surfaces to inside, thethrough hole can be easily filled by the conducting layer.

As a result of this, an interposer whose manufacturing process is simpleand the void is not generated inside of the through hole, can beprovided.

Preferably, areas of the first opening and the second opening aredifferent.

Because the values of the opening area on one surface side and anothersurface side are different, the wiring rules for the both surfaces canbe independently settled, and wider degree of freedom for designing awiring width and a wiring layout can be obtained.

More preferably, the through hole has a cylindrical portion between thesurface of the one side and the surface of another side of thesubstrate.

In accordance with still another aspect of the present invention, aninterposer has a through hole, in which the through hole is made from asurface of one side of the substrate to a surface of another side; thethrough hole has a first opening area at the surface of the one side,and the first opening area becomes smaller in succession as the holegoes from the surface of the one side to the surface of the anotherside; and a conducting layer is formed in the through hole.

In accordance with still another aspect of the present invention, amanufacturing method for the interposer including steps of: preparing asubstrate which has one surface and another surface opposed to the onesurface; forming a through hole by performing an etching such that anopening area of the through hole becomes smaller in succession as thehole goes from the surface of the one side and from the surface of theanother side to inside; and forming a conducting layer in the throughhole.

Because in this manufacturing method for interposer the through hole isformed by performing an etching such that an opening area of the throughhole becomes smaller in succession as it goes from the surface of theone side and from the surface of the another side to inside, theconducting layer can be formed without any discontinuity inside of thethrough hole when the conducting layer is formed in the through hole.

As a result, a manufacturing method for the interposer which is simpleand the void is not generated inside of the through hole, can beprovided.

Preferably, the etching is performed such that the area of the openingof the surface on the one side and the area of the opening of thesurface on another side are different.

More preferably, the manufacturing method further includes a step offorming a through hole whose opening area is constant from the surfaceof the one side to the surface of another side.

In accordance with still another aspect of the present invention, amanufacturing method for interposer including steps of: preparing asubstrate which has one surface and another surface opposed to the onesurface; forming a through hole by performing an etching such that anopening area of the through hole becomes smaller in succession as thehole goes from the surface of the one side to the surface of the anotherside; and forming a conducting layer in the through hole.

At this point, it is preferable that the etching is performed utilizingdry etching. The conducting layer may be formed utilizing evaporation,electroplated coating or electroless plating.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is a diagram showing a manufacturing process of an interposeraccording to the first embodiment of the present invention step by step;

FIG. 1B is a diagram showing a manufacturing process of the interposeraccording to the first embodiment of the present invention step by step;

FIG. 1C is a diagram showing a manufacturing process of the interposeraccording to the first embodiment of the present invention step by step;

FIG. 1D is a diagram showing a manufacturing process of the interposeraccording to the first embodiment of the present invention step by step;

FIG. 2 is a diagram showing a manufacturing process of an interposeraccording to the second embodiment of the present invention;

FIG. 3A is a diagram to show a shape of a through hole to which thethird embodiment of the present invention is applied;

FIG. 3B is a diagram showing a shape of the through hole to which thethird embodiment of the present invention is applied;

FIG. 4A is a diagram showing a manufacturing process of an interposeraccording to the forth embodiment of the present invention step by step;

FIG. 4B is a diagram showing a manufacturing process of the interposeraccording to the fourth embodiment of the present invention step bystep;

FIG. 4C is a diagram showing a manufacturing process of the interposeraccording to the forth embodiment of the present invention step by step;

FIG. 4D is a diagram showing a manufacturing process of the interposeraccording to the forth embodiment of the present invention step by step;

FIG. 5 is a cross sectional view showing a through hole on a substrateof an interposer according to the fifth embodiment of the presentinvention;

FIG. 6 is a cross sectional view showing a through hole on a substrateof an interposer according to the sixth embodiment of the presentinvention;

FIG. 7 is a perspective view showing a substrate of the interposer whichhas the cross sectional structure shown in FIG. 6;

FIG. 8A is a cross sectional view showing a through hole of aninterposer according to the seventh embodiment of the present invention;

FIG. 8B is a diagram showing a manufacturing process of the through holefor the interposer according to the seventh embodiment of the presentinvention; and

FIG. 9 is a diagram to explain a problem of an interposer in the priorart technology.

BEST MODE FOR CARRYING OUT THE INVENTION (1) First Embodiment

Hereinafter, the first embodiment according to the present inventionwill be described with reference to the accompanying drawings. FIG.1A-FIG. 1D are diagrams to show step by step a manufacturing process ofan interposer according to the first embodiment of the presentinvention. Referring to FIG. 1A-FIG. 1D, firstly a silicon substrate 10having a front surface 11 and a back surface 12 is prepared, and athrough hole 13 is opened on the substrate (FIG. 1A). At this point, thethrough hole 13 may be formed having a shape whose center portion isconcave as shown in FIG. 1A as the interposer in the prior art. In thisstate, then, an insulating film which is not shown in the drawing, isformed on the substrate 10 including inside of the through hole 13. Thisinsulating film may be made of SiO2, SiN and the like and is formed bysputtering, CVD or oxidization.

Next, Ti layer (not shown) as a barrier layer is formed by sputteringand the like around the through hole 13 where the insulating layer isformed on the back surface 12 of the substrate 10. Then, a seed layer 14(a base layer for an electrode to flow current for electroplating) madeout of Cu is formed on the barrier layer by sputtering and the like(FIG. 1B). An electroplated coating is performed from the back surface12 based on the Cu seed layer 14. This electroplated coating isperformed till an edge surface of the electroplating meets to close thethrough hole 13 at the back surface 12 so as to form an electrode layerfor the electroplated coating of the electroplated coating layer 15 madeout of Cu (FIG. 1C).

Next, an electroplated coating of Cu is performed to the front surface11 utilizing the electroplated coating layer 15 of Cu as an electrode.By these steps, an electroplated coating layer of Cu grows in adirection shown by an arrow in FIG. 1D, and an electroplated coatinglayer 16 is prepared (FIG. 1D).

As described above, according to this embodiment, the through hole 13can be made as the conducting layer of Cu without generating the voidinside of the through hole even when the concave shaped hole is formedinside of the through hole 13.

At this point in the embodiment described above, though Ti is utilizedas the barrier layer, this layer can be omitted.

(2) Second Embodiment

Next, an explanation will be given on the second embodiment. FIG. 2 is adiagram to show a manufacturing process of an interposer according tothe second embodiment corresponding to FIG. 1D of the first embodiment,and the interposer has basically the same structure as shown in FIG. 1.Referring to FIG. 2, in this second embodiment, a through hole 23 isformed on a silicon substrate 20, and the through hole 23 is filled witha seed layer 24, an electrode layer 25 for electroplated coating andelectroplated coating layer 26.

Though in the first embodiment, the seed layer and the electroplatedcoating layer made out of Cu are formed on the silicon substrate, inthis embodiment the seed layer 24, the electrode layer 25 forelectroplating and the electroplated coating layer 26 are made out ofnot only Cu but any material such as Ni, Cr, Au, Ag and the like as faras the electroplated coating can be performed. The material for the seedlayer 24, the electrode layer 25 for electroplated coating and theelectroplated coating layer 26 may be different from one another. Forexample, the seed layer may be made out of Cu and the electroplating ofAu may be performed utilizing the seed layer as the electrode layer forelectroplated coating.

(3) Third Embodiment

Next, an explanation will be given on the third embodiment of thepresent invention. FIG. 3 is a diagram to show a shape of the throughhole to which an interposer according to the third embodiment of thepresent invention is applied. Though in the first and the secondembodiments, the present invention is applied to the through holeshaving the shape whose center portion becomes concave, the presentinvention can be applied to the substrate 30 with the through hole 31having a cylindrical shape (FIG. 3A) and the through hole 32 having adiameter which becomes smaller in succession as the hole goes from thefront surface to the back surface (FIG. 3B).

Though in the above described embodiments, the explanation is made onthe embodiments utilizing the silicon substrate as a material for thesubstrate, these embodiments should not be considered as the restrictedexamples, and the present invention is applicable to the insulatingsubstrate made out of such as glass and sapphire. In these cases,forming of the insulating layer described above is not necessary.

Though in the embodiments described above, the explanation is made onthe cases in which filling of the conducting material into the throughhole is performed by electroplated coating, the present invention shouldnot be restricted to these examples, the filling may be performed byelectroless plated coating.

(4) Fourth Embodiment

Next, an explanation will be given on the fourth embodiment of thepresent invention. FIG. 4A-FIG. 4D are diagrams to show step by step amanufacturing process of an interposer according to the fourthembodiment of the present invention. Referring to FIG. 4A-FIG. 4D, inthis embodiment firstly, a silicon substrate 40 having a front surface41 and a back surface 45 is prepared (FIG. 4A). Then, a front surfacehole 42 is formed which has a diameter that becomes smaller insuccession as it goes into inside at a predetermined position on thefront surface 41 of the substrate 40 by dry etching from the frontsurface 41. To be more specific, the etching is performed withappropriate combination of etching conditions of the isotropic etchingand the anisotropic etching.

Next, a back surface hole 46 is formed which has diameter that becomessmaller in succession as it goes into inside on the back surface 45 ofthe substrate 40 by the same manner from the back surface 45, and centeraxis of the both holes are made substantially into a line at the centerportion of the substrate 40. As described above, a through hole 49 isformed having a diameter that becomes smaller in succession as it goesinto inside from the front surface 41 and the back surface 45 on thesubstrate 40 (FIG. 4B).

In this state, then, an insulating film which is not shown in thedrawing, is formed on the substrate 40 including inside of the throughhole 49. This insulating film may be made out of SiO2, SiN and the likeand is formed by sputtering, CVD or oxidization.

Then the seed layers 43, 47 to be seeds of the electroplated coatinglayers are formed inside of the through hole 46, 49 and at an adjoiningarea of the front surface 41 and the back surface 45 around the throughhole 46, 49 on the insulating film by sputtering (FIG. 4C). At thispoint, because the through hole 46, 49 has not the shape whose centerportion becomes concave as in the prior art technology, the seed layers43, 47 can be formed easily inside of the through hole 46, 49 and aroundthe opening of the through hole 46, 49 of the front surface 41 and theback surface 45 continuing from inside.

Next, the electroplated coating or the electroless-plated coating isperformed on the through hole 46, 49 based on the seed layer 43, 47, andthe conducting layer 44 made of Cu and the like is formed (FIG. 4D). Asa result, the interposer which has the conducting layer without anygeneration of the void inside of the through hole 46, 49 can be formedutilizing simple manufacturing process.

Though the explanation is made about the case in which only one throughhole 46, 49 is made in the above described embodiment, a plurality ofthrough holes 46, 49 may be formed.

At this point, it is contemplated that the similar through hole havingslopes inside may be formed by the wet etching. However by the wetetching, there may be a problem that a slope of the through hole becomestoo broad to get a predetermined shape of the through hole. To thecontrary, by the dry etching, the through hole with a predeterminedshape can be formed because the manufacturing control of the slope ofthe through hole is easy.

(5) Fifth Embodiment

Next, an explanation will be given on the fifth embodiment of thepresent invention. FIG. 5 is a cross sectional view to show a throughhole on the substrate of an interposer according to the fifth embodimentof the present invention corresponding to FIG. 4B of the fourthembodiment. In the fourth embodiment, the explanation is made in a casein which etching is performed from both sides of the silicon substrate40. In this embodiment a through hole 51 whose diameter becomes smalleras it goes inside from only one surface of the front surface or the backsurface of the substrate 50, is formed as shown in FIG. 5 by performingthe etching only from the front surface of the silicon substrate 50.Further, the through hole 51 is made to be conductive by filling aconductive material inside of the through hole 51 by the same method asshown in FIG. 4A to FIG. 4D.

Even in this embodiment, the seed layer and the conductive layer basedon the seed layer, can be formed easily as in the fourth embodiment, andthe same effect can be obtained as the fourth embodiment.

(6) Sixth Embodiment

Next, an explanation will be given on the further different embodimentof the present invention. FIG. 6 is a cross sectional view to show athrough hole on the substrate 60 of an interposer according to the sixthembodiment of the present invention corresponding to FIG. 4B of thefourth embodiment.

In this embodiment, the holes 63, 64 are formed whose diameters becomerespectively smaller as they go inside from the front surface 61 and theback surface 62 on the substrate 60 similar to the fourth embodiment,however, the diameters of them are different at the front surface 61 andthe back surface 62. In other words, referring to FIG. 6, the substrate60 has a thickness “t”, the hole on the front surface 61 has a diameter“a” and the hole on the back surface 62 has a diameter “b” where a<b.The hole 63 on the front surface 61 has a depth “t1” and the hole 64 onthe back surface 62 has a depth “t2” to the inside of the hole. As aresult, a step portion 68 is formed inside of the substrate 60. At thispoint, etching for different diameters may be performed from both of thefront surface 61 and the back surface 62 similar to the fourthembodiment so as to form the front side hole 63 and the back side hole64 with different diameters and to form the through hole 69 at anyposition whereby a structure without the step portion 68 may be formedas shown by the dotted line in the drawing. After manufacturing asdescribed above, the inside of the through hole 69 is filled with theconducting layer.

FIG. 7 is a perspective view to show the substrate 60 of the interposerwhich has the cross sectional structure shown in FIG. 6. Referring toFIG. 7 in this embodiment, because diameters of the through hole 69 aredetermined at the front surface 61 and the back surface 62 as describedabove, wiring area 67 can be made wider at the front surface 61 than atthe back surface 62. By this arrangement, wiring rules for the frontsurface 61 and the back surface 62 can be independently settled, andwider degree of freedom for designing a wiring width and a wiring layoutcan be obtained on the front surface 61. Moreover, because size of theopening portion of the through hole 69 is designed larger at the backsurface 62, process window for a through wiring can be expanded suchthat electroplating liquid penetrates well, the aspect ratio of thethrough hole becomes small, and the like.

At this point, the wiring 65 in FIG. 7 is performed via terminals 66 b,66 c which are formed in the pads 63 b, 63 c formed on the surface ofthe conducting layer filled in the hole 63.

(7) Seventh Embodiment

Next, an explanation will be given on the seventh embodiment of thepresent invention. FIG. 8A is a diagram to show a cross sectionalstructure of the substrate 70 in this embodiment of the presentinvention. Referring to FIG. 8A in this embodiment, the through hole 76has semispherical opening portions 72, 74 on the front surface 71 andthe back surface 75 of the substrate 70 and a cylindrical hole 73 isformed at the central portion of the through hole 76.

By forming the through hole 76 with the above described shape,penetration of the electroplating liquid is improved and improvement ofadhesion of the electroplated coating can be expected. Further,suppression of peeling of the adhered electroplated coating can beexpected.

Next, the conducting hole is completed by filling of the through hole 76with the conductive material utilizing the electroplated coating and thelike similar to the embodiments described above.

Next, explanation will be made how to manufacture the through hole 76 inthis embodiment. FIG. 8B is a diagram to show a manufacturing process ofthe through hole 76 shown in FIG. 8A. Referring to FIG. 8B, a resist 77is located on the surface 71 of the substrate 70, and the openingportion is formed on a predetermined position to perform isotropicetching. By this, the semispherical opening portion 72 is formed on thefront surface 71 side. Similarly, the semispherical opening portion 74on the back surface 75 side is also formed. Then, the anisotropicetching is performed to form the cylindrical hole 73.

At this point, forming of the cylindrical hole in this embodiment may beapplied to the above described respective embodiments.

Though in the above described embodiments explanation is made on casesthat circular or cylindrical through holes are utilized, the presentinvention should not be restricted to these embodiments, and arectangular or a polygonal through hole may be used.

Though in the above described embodiments, explanation is made on casesthat the conducting layers are formed utilizing the electroplatedcoating based on the seed layer, the present invention should not berestricted to these embodiments, and the conducting layer may be formedonly by the seed layer.

Though in the above described embodiments, explanation is made on casesthat filling of the conducting material into the through hole isperformed by the electroplated coating, the present invention should notbe restricted to these embodiments, and the filling may be performed bythe electroless plating or the evaporation.

Though in the above described embodiments, explanation is made on casesthat forming of the through hole is performed by utilizing the dryetching, the present invention should not be restricted to theseembodiments, and the forming may be performed by utilizing the wetetching.

INDUSTRIAL APPLICABILITY

The manufacturing method of the interposer in accordance with thepresent invention can be utilized advantageously as a manufacturingmethod of the interposer in which the void is not generated in thethrough hole because the conducting layer by the electroplated coatingis surely formed at the through hole from one side of the substrate toanother side.

1. An interposer comprising: a substrate which has one surface, anothersurface opposed to said one surface, and a through hole passing throughfrom said one surface to said another surface; a seed layer which isformed at an opening portion of said through hole on said one surfaceside of said substrate; an electrode layer for electroplated coatingwhich is formed by covering said seed layer; and an electroplatedcoating layer which extends from said electrode layer for electroplatedcoating to said another surface side to fill said through hole.
 2. Theinterposer according to claim 1, wherein said through hole has a shapewhose center portion is concave.
 3. The interposer according to claim 1,wherein said seed layer, said electrode layer for electroplated coatingand said electroplated coating layer are made out of the same material.4. The interposer according to claim 1, wherein at least two of saidseed layer, said electrode layer for electroplated coating and saidelectroplated coating layer are made out of different materials.
 5. Amethod for manufacturing an interposer comprising steps of: preparing asubstrate which has one surface and another surface opposed to said onesurface; forming a through hole on said substrate; forming a seed layerat an opening portion of said through hole on said one surface side; andfilling said through hole by forming an electroplated coating layer fromsaid seed layer on said one surface side to said another surface side.6. The method for manufacturing an interposer according to claim 5,wherein said step of filling said through hole by forming anelectroplated coating layer from said seed layer on said one surfaceside to said another surface side includes steps of: forming anelectrode layer for electroplated coating to close said through hole atsaid one surface side; and forming said electroplated coating layerutilizing said electrode layer.
 7. The method for manufacturing aninterposer according to claim 5, wherein said step of forming thethrough hole includes a step of forming a through hole whose centerportion becomes concave.
 8. The method for manufacturing an interposeraccording to claim 6, wherein said seed layer, said electrode layer forelectroplated coating and said electroplated coating layer are made outof the same material.
 9. The method for manufacturing an interposeraccording to claim 6, wherein at least two of said seed layer, saidelectrode layer for electroplated coating and said electroplated coatinglayer are made out of different materials.
 10. An interposer having athrough hole wherein: said through hole is made from a surface of oneside of said substrate to a surface of another side; said through holehas a first opening area at said surface of said one side and theopening area becomes smaller in succession as the hole goes from saidsurface to inside and has a second opening area at said surface of saidanother side and the opening area becomes smaller in succession as thehole goes from said surface of another side to inside; and a conductinglayer is formed on said through hole.
 11. The interposer according toclaim 10, wherein the first opening area and the second opening area aredifferent.
 12. The manufacturing method for the interposer according toclaim 10, wherein said through hole has a cylindrical hole part havingthe same opening area between said surfaces of said one side and saidanother side.
 13. The interposer according to claim 1, wherein saidthrough hole has a smaller opening area in succession as it goes fromsaid surface of said one side to said surface of said another side. 14.A method for manufacturing an interposer comprising steps of: preparinga substrate which has one surface and another surface opposed to the onesurface; forming a through hole by performing an etching such that anopening area of said through hole becomes smaller in succession as thehole goes from said surface of said one side and from said surface ofsaid another side to inside; and forming a conducting layer in saidthrough hole.
 15. The method for manufacturing an interposer accordingto claim 14, wherein said etching is performed such that said openingarea of said surface on said one side and said opening area of saidsurface on said another side are different.
 16. The method formanufacturing an interposer according to claim 14 further comprising astep of forming a through hole whose opening area at said surface ofsaid one side is the same as that at said surface of said another side.17. The method for manufacturing the interposer according to claim 5,wherein said step of forming said through hole on said substrate isperformed utilizing etching such that an opening area of said throughhole becomes smaller in succession as the hole goes from one side of thesubstrate to another side.
 18. The method for manufacturing aninterposer according to claim 14, wherein said etching is performedutilizing dry etching.
 19. The method for manufacturing an interposeraccording to claim 14, wherein said step of forming said conductinglayer is performed utilizing evaporation, electroplated coating orelectroless plating.